Chelmsford Crown Court heard a hoist had been weakened by overloading and Judge David Turner said the incident was "not a tragic one-off" incident.

There was a pattern of poor compliance with health and safety regulations that had led to the fall, Judge Turner said.

He also told Network Rail to pay £85,000 costs.

A post-mortem examination revealed Mr Slater, of Harold Wood, died from head and spinal injuries.

The court heard that in June 2008, Mr Slater and two colleagues were working at height in a basket welded to the hydraulic arm of a Unimog hoist on the Norwich to London line.

'Deep regret'

However, the weld failed and sent the men crashing to the track below.

There was a 350kg (770lb) weight limit on the platform, but on the day before the accident it had been overloaded at times by up to 100kg (220lb), the court was told.

It was not the first time that overloading of the baskets had been reported and the alarm on the hoist, which warned of excessive weight, had been muted, the court was told.

Network Rail admitted failing to ensure that work equipment provided for the use of its employees was suitable for the the lifting and support of employees, their tools and other items whilst engaged in the maintenance and repair of overhead line equipment.

Two other charges have remained on file.

Network Rail expressed its "deep regret and remorse" at Mr Slater's death and the injuries sustained by his two colleagues.

It admitted it had failed to address overloading in normal use, but refuted claims its platforms had been used as a crane.

At Mr Slater's inquest in 2010, Essex coroner Caroline Beasley-Murray said she would write to the Office of Rail Regulation asking inspectors to ensure new welds on lifting gear had been fully tested.

Metallurgist Keith Birkitt told the inquest that the quality of the weld on the basket had been "poor in places".